


Trails of Shadow

by darkling59



Series: Annals of the Incomplete [46]
Category: Bleach
Language: English
Status: Completed
Published: 2015-03-16
Updated: 2015-03-16
Packaged: 2018-03-18 01:23:39
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,370
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3550862
Author URL: https://archiveofourown.org/users/darkling59/pseuds/darkling59
Summary: <blockquote class="userstuff">
              <p>The past of Sosuke Aizen is shrouded in mystery and death.</p>
            </blockquote>





	Trails of Shadow

_Every hero has a beginning, a definitive moment in their history that led to their present actions. Every hero has a past. So does every villain. Sosuke Aizen is no different._

* * *

Once upon a time, young Sosuke Aizen was terrified of hollows. He lived with a pack of other children in one of the less destitute Rukongai districts, listening to the stories of courageous shinigami and monstrous hollows with wide, shining eyes.

But, while the other children were content to hide in their beds and whisper about how someday _they_ would be a shinigami and a hero and then the hollows would fear _them_ , Sosuke wondered why, if the hollows were such dumb, powerful beasts, did the shinigami not tame that power and _use_ it?

Theoretically, the shinigami would never have to lift a finger if they managed to tame hollows to fight.

The idea took seed and festered, growing to consume little Sosuke’s thoughts. Maybe, if he had confided in one of the other children or the adults, someone would have managed to uproot it. But, even then, Sosuke knew that his thoughts would not be welcome and, instead, pasted a bland smile on his face and agreed with the other children, disguising the dark turn of his thoughts.

As he grew and learned more about the shinigami, heard more stories and actually came to discern truth from lies, his dissatisfaction with the so-called ‘protectors’ grew. It seemed to him that they were inexcusably lax in their actions, leaving hollows to rampage more often than not and responding slowly and even then only when it benefited Seireitei.

He could do better.

This new thought overtook his previous obsession.

And why not? The shinigami were inept; _anyone_ could do better. Sosuke was smart, quick, strong, and willing to make sacrifices when necessary. Just a cursory examination of their patrol schedule and strategies was enough to schedule an ‘accidental’ meeting with the nineteenth seat of squad 7, Ganjo Fushiki. Ganjo was bored with meaningless patrols and welcomed a break in routine. He quickly took a liking to the attentive, curious youngster.

Sosuke quickly figured out that Ganju was stupid and weak; the man was more interested in proclaiming his glory days than in fighting hollows and he could only hold his shikai for 30 seconds. Still, he was a treasure trove of information and some pointed questions brought the older man to reminisce about his days in the academy. By feigning interest, Sosuke learned about zanpakuto spirits, shikai, bankai, lieutenants, captains, kido, and the living world. Unfortunately, Ganjo knew little about hollows- the only times he’d fought were during academy training sessions.

Still, Sosuke was able to extrapolate how to find his inner world and figure out how kido worked, although he couldn’t practice without more information or supplies.

Sadly, Ganjo died in a horrible accident less than a year after meeting Sosuke, the day after he ran out of stories to tell. When people spoke about it later, they lamented how someone as young as Sosuke was forced to watch such a horrible spectacle.

No one noticed the ‘new’ sword at boy’s hip.

He enrolled in the academy two days later.

* * *

During his time at the academy, Sosuke learned that not all shinigami were as easy to fool as Ganjo. Some were frightfully observant, in fact. He had to carefully foster a public persona; pointed questions became a thing of the past, as did curiosity. It wouldn’t do to tip his hand early, after all.

Classes were easy; he’d already managed to call his shikai and mastering other techniques and incantations was almost boring. However, he purposely kept from scoring _too_ high. He had to rank high enough to become at least a third seat upon graduation, but not high enough to be considered a prodigy.

Smart enough to be taken seriously, but not smart enough to draw unnecessary attention.

His first glimpse of a hollow came during a yearly training exercise. The class was deployed to the 53rd district in response to six deaths, a result of hollow attacks. Upon arrival, they found an extremely weak hollow skulking around the woods, snacking on lone travelers. It wasn’t even powerful enough to take on multiple civilians at once.

At least, until Sosuke saw his peers in action.

They were even _worse_ than the hollow.

He watched in disbelief as they stumbled all over each other trying to get a swing in, eagerly jumping into danger and getting in each other’s way, making the situation considerably more dangerous with their recklessness.

If he’d been less controlled, Sosuke would have face palmed. As it was, he took the situation for the opportunity it was and lured the hollow away so he could face it alone, using his zanpakuto to conceal his presence.

It was then that he made his first big discovery: hollows, even weak ones, were _self-aware._

The academy taught that hollows were monsters, lost souls driven by mindless hunger. Occasionally they retained the ability to speak, but it was only used instinctively to find and lure prey. Ranking shinigami were warned to never look at the face of a hollow without its mask, because it would give them a glance of what the creature had once been and could make them hesitate. That hesitation could be deadly. The appearance was just an illusion; the instructors made it abundantly clear that there was nothing of the original human left, and that hollows did not deserve sympathy.

This creature, a common hollow, did not fit that profile. True, it mocked and gibed, trying to lure Sosuke closer. However, it also hung back in response to a threat, noticed simple attack patterns, planned its own attacks, and was willing to retreat when it became clear that it wouldn’t win.

It didn’t make it far, one quick strike knocked out its legs and let Sosuke examine it at his leisure (turns out hollows could beg, as well), before cutting the mask and getting a glimpse of the human face before it dissolved. The creature was disappointingly easy to kill.

Was this the monster of his childhood, that every plus feared? Then again, the pluses at least had an excuse- each one of them was even pathetically weaker than even this hollow. But, if _this_ was the shinigami’s dreaded enemy, just how weak were _they_?

His dream of using hollows to fight hollows suddenly seemed like a useless undertaking. Maybe he should be training the _hollows_ to use the _shinigami_.

Hah! That would be the day.

* * *

The problem with such thoughts, even the comical ones, is that they tend to take root and spread, especially in a fertile mind. And Sosuke was nothing if not imaginative. His childhood idea to train hollows quickly flared back into life.

He was deadly bored in the academy, taking and passing courses with ease, so the distraction was welcome. He couldn’t approach anyone else about it, of course. The governing system of Seireitei was such a paranoid dinosaur that any ‘radical’ claims about changing fighting protocol or considering new evidence and data about hollows was tantamount to treason.

He scoured the archives and history books, and made good use of his instructors; asking only the least controversial questions and even then only in a roundabout manner. Not a one realized they were talking about hollows rather than fighting or kido.

Almost no one.

Sosuke learned pretty quickly to avoid the piercing gaze of kido master Tessai Tsukabishi, and the suspicious sneer of 5th squad captain Hirako Shinji. Both of them were of a particularly annoying sect of shinigami; those observant enough, or pessimistic enough, to question Sosuke’s pleasant mask and intelligent enough to draw the correct conclusions from the information he was asking for.

Still, that sect was small and shrinking due to Sosuke’s careful interference, and even more careful application of his shikai.

* * *

The first time he snuck out of the academy and into the human world was a bit of a culture shock. It had been over two hundred years since his rebirth in Rukongai and he remembered nothing of his first life before that. If pressed, he would have assumed the human world would look like the less wealthy districts. After all, humans were too simple and defenseless to protect themselves from something as weak as minor hollows, how could they possibly be any more advanced than Seireitei?

Needless to say, Russia was a far cry from what he’d been expecting. Not only was the hollow outside of Soul Society’s domain, Sosuke also had to walk a tightrope with the humans and the local spiritual enforcers.

In the end, he didn’t even get close enough to speak with the hollow but he did learn quite a bit about humans and politics. It gave him much to think about, when he snuck back through the gate and found himself on the wrong side of Hirako Shinji’s triumphant glare.

It was a long time before he snuck out again.

* * *

Despite the initial disaster, Sosuke eventually became adept at sneaking into the human world and hunting hollows. Well…’studying’ would be more accurate. Most of them were ridiculously weak but some had fascinating abilities- camouflage, electrokinesis, echolocation, pyrokinesis…it was rare to find two hollows with the same set of traits.

Surprisingly, it was during a sanctioned academy training session that his next epiphany occurred. One of the students encountered a hollow with a serrated, extendable tongue that was similar in shape to the boy’s zanpakuto. As a result, the shinigami had a difficult time taking the offensive and took heavy injuries. When the rest of the group found him, they originally thought he had been attacked with his own sword.

It was only a hop, skip, and a jump from weak hollows having parallel powers to young shinigami, to strong hollows having the powers of older shinigami, perhaps even captain-class…? And just imagine how powerful a _vasto lorde_ must be!

Not to mention, hollows had the added benefit of being able to manifest multiple abilities without the constraints of a zanpakuto and a seeming instinctual ability to do what took years, decades even, for shinigami to master with training.

If the powers were so similar, so easy to parallel, then why couldn’t a shinigami gain those same benefits?

Was there any way to gain a hollow’s abilities without becoming a hollow?

* * *

The first experiments started a week later.

It was small things at first: catching hollows in the human world and studying them, watching pluses transform and documenting the process, examining the composition of a hollow’s mask and skin, etc.

Over the next fifty years, it quickly escalated. Sosuke found he had a knack for biochemistry, reiatsu extraction and materialization, and genetic engineering. His used a creative combination of different techniques to begin studying how shinigami and hollow traits could be combined and manipulated in one body.

Test subjects and material were surprisingly easy to procure. Humans came straight off the streets of Rukongai (they were rarely missed, and always attributed to hollows when they were) and hollows were easily lured from the human world and Hueco Mundo.

It only took a few years of experimentation before he was able to begin producing hollows with shinigami traits. Unfortunately, he was still having no luck with the opposite reaction, and the situation was made more difficult by a lack of shinigami test subjects.

So far, both spirits from Rukongai and shinigami either dissolved or simply died when exposed to the process.

Hollows, for all their bestial nature, were much better at adaptation and evolution than shinigami…their very existence depended on flexibility and a fast learning curve.

* * *

Life in the ‘real world’ did not slow down while Sosuke was focused on his experiments. His studies at the academy were completed one year early and he was accepted into the ranks of the fifth division under captain Hirako Shinji. He met first Gin Ichimaru, then Kaname Tousen and recognized their potential, beginning to groom them as subordinates from their first meetings. Somehow, Gin seemed to recognize this but instead of fleeing and forcing Sosuke to kill him, the boy simply smiled and followed close behind.

Sosuke vowed to watch him closely; he was fast, smart, and deadly despite his size.

He was so focused on his own life and studies that he completely missed the rising star of Urahara Kisuke, who had finished at the academy a generation before and was finally coming into his own as a scientist and a frighteningly powerful shinigami.

Still, it would be years before Urahara was a threat. Hirako was by far the bigger thorn in Sosuke’s side.

He was, however, a very _useful_ thorn. Sosuke knew Hirako was paranoid and suspicious and he played on those fears, subtly trying to force his captain’s hand. Eventually, patience and persistence paid off and the older man decided he would rather keep Sosuke close than let him roam.

His promotion to lieutenant was greeted enthusiastically by the entire fifth division, with the only exception of its captain.

* * *

It quickly became obvious that being a lieutenant was much, _much_ more time consuming than being a student or seated officer. It was nearly a year later that he was able to resume his experiments, and even then he had to use his shikai to ward off unwanted attention. It was a relatively small price to pay for increased influence and access to archives and supplies that he would never have managed to get otherwise. Gin turned out to be invaluable- sneaky, smart, and charming enough to go anywhere, get anything that Sosuke needed.

It was becoming _imperative_ to figure out what was going on in that little silver head. So far, Sosuke had not been able to find any reason for Gin to be on his side, other than personal preference. But, if that was the case, why become a shinigami in the first place?

Still, it was not a time sensitive problem so it got shuffled to the back burner. Sosuke would simply keep him close and under observation. At the first sign of any suspicious intentions…well.

New shinigami test subjects were always welcome.

**Author's Note:**

> Written in 2012, before the Quincy arc. I've no idea if Aizen's past has been discussed since then, but this was written without any knowledge of it.


End file.
